摘要:
1.设计索引的原则是什么? 1. 为频繁查询的字段建立索引2.选择区分度大的列作为索引性别 男 女 加索引和不加区别不大超过基线,比如查询的数据集大于30%3.尽量为ORDER BY 和 GROUP BY 后面的字段建立索引因为在GROUP BY 的时候也要先根据 GROUP BY 后面的字段排序, 阅读全文
摘要:
1. 监控请求数据 The total number of connected clients and their states (active, idle in transaction, waiting) SELECT COUNT ( * ) FILTER ( WHERE STATE IS NOT 阅读全文
摘要:
could not locate a valid checkpoint record 3. 执行修复命令:/usr/pgsql-11/bin/pg_resetwal -f /var/lib/pgsql/11/data PANIC: could not locate a valid checkpoin 阅读全文